The disclosure of Japanese Patent Application No. 2001-402054 filed Dec. 28, 2001 including the specification, drawings and claims is incorporated herein by reference in its entirety.
1. Field of Invention
The invention relates to a vehicle control apparatus, a control method and a control program which can execute control of shifting of an automatic transmission apparatus capable of changing a speed of rotation of a driving source and outputting this rotation, in accordance with road information and vehicle state information.
2. Description of Related Art
Conventionally, in order to control engine braking force in accordance with the expectations of a driver with respect to the condition of the road the vehicle is running on, a vehicle control apparatus or so-called navigation assisted shift control has been proposed. This type of vehicle control apparatus for controlling an automatic transmission based on information concerning the road ahead, and the like, detected by a navigation device, is disclosed in Japanese Patent Laid-Open Publication No. 11-230322.
The disclosed navigation assisted shift control mentioned above calculates a predetermined target input shaft rotation number such that engine brake is applied in accordance with the road information. The road information includes information concerning the road configuration (for example, corner shape, road gradient) detected by a navigation device, road condition (for example, degree of road surface smoothness, snow fall) detected by various sensors, and operating condition (for example, vehicle speed, intentions of the driver with respect to deceleration), and the like. The navigation assisted shift control uses the predetermined target to control a shift ratio and a shifting speed of a continuous variable transmission (CVT), such that the engine braking force accords with the expectations of the driver. As a result, the drivability of the vehicle is improved, and in particular, the stability of the vehicle when driving around corners and curves is improved (so-called cornering control is executed).
However, for example, when a vehicle enters a first corner from a straight road, the driver can see the first corner at an early stage. Thus, it is comparatively easy for the driver to realize that a corner exists prior to entering the first corner. On the other hand, for example, in the case of a road which has two corners or more in close succession, it is difficult to see the second corner and subsequent corners that will be entered, as the distance between the corners is short, and/or there may be obstructions, such as buildings and the like. As a result, it is difficult to see that next corner at an early stage. Thus, before entering the next corner, the driver may not realize that there is a corner ahead early enough, or indeed, may not realize the corner exists at all.
Moreover, in the case of the shifting speed of the navigation assisted shift control, the magnitude of the shifting speed with respect to the aforementioned information concerning operating state, and the like, is set in advance. Accordingly, in the case of entering the first corner from the straight road, even if the driver realizes the first corner exists, the strength of the engine brake obtained may not be in accordance with the expectations of the driver. As a result, the driver, or another occupant, may feel a sense of discomfort.
On the other hand, in the case of entering the second or subsequent corners in the example described above, even when the driver does not realize there is a second corner early enough, or indeed, does not realize that a second corner exists at all, a degree of engine brake which the driver is not expecting (anticipating) is applied. As a result, the driver or the other occupant may feel a sense of discomfort. In addition, as the vehicle continues running around the next corner in the example, the aforementioned unexpected degree of brake engine brake is applied. Accordingly, as the vehicle is turning, a degree of engine brake which is not expected (anticipated) is applied, and as a result the driver or the other occupant may feel a sense of discomfort.
It is an object of the invention to provide a vehicle control apparatus, a control method and a control program which can solve the aforementioned problems which relate to the described related art. In the vehicle control apparatus, the control method and the control program according to the invention, a shifting speed setting device sets a shifting speed to a predetermined shifting speed such that shifting is rapidly executed, when a control by a shift control device is initiated. When shifting needs to be executed during the execution of the control by the shift control device, the shifting speed is set to be lower than the aforementioned predetermined shifting speed.
According to the first aspect of the invention, the shift control device calculates the predetermined target input shaft rotation number based on the road information and the vehicle state information, and controls the input shaft rotation number such that the input shaft rotation number becomes equal to the predetermined target input shaft rotation number, by executing shifting of the shift execution device. Moreover, the shifting speed setting device sets the shifting speed, when control based on the road information begins after switching from control based on the vehicle state information by the shift control device, to the predetermined shifting speed such that shifting is executed rapidly, and sets the shifting speed, when shifting needs to be executed during control based on the road information by the shift control device, such that the shifting speed is lower than the predetermined shifting speed. Accordingly, the control by the shift control device can respond to differences in the expectation of a driver with respect to vehicle acceleration change magnitude, depending on whether it is a time of starting control based on the road information after switching from control based on the vehicle state information, or a time during which control based on road information is in-progress. As a result, it is possible to prevent the driver from feeling a sense of discomfort.
Further, according to the first aspect of the invention, the road information shift control device calculates the predetermined target input shaft rotation number based on the road information, and controls the input shaft rotation number such the input shaft rotation number becomes equal to the predetermined target input shaft rotation number, by executing shifting of the shift execution device. Furthermore, the continuous control detection device detects that shifting needs to be executed while control by the road information shift control device is continued during control by the road information shift control device. Moreover, the shifting speed setting device sets the shifting speed to a predetermined shifting speed such that shifting is executed rapidly when control by the road information shift control device starts, and sets the shifting speed such that the shifting speed is lower than the predetermined shifting speed when shifting needs to be executed during control by the road information control device, based on the detection result of the continuous control detection device. Accordingly, it is possible to detect the need to execute shifting while continuing control by the road information shift control device. As a result, the control by the shift control device can respond to differences in the expectation of the driver with respect to the vehicle acceleration change magnitude, depending on whether the control by the shift control device is starting or in-progress. As a result, it is possible to prevent the driver, or an occupant from feeling a sense of discomfort.
Also, according to the first aspect of the invention, the road information is information which includes at least one of the corner shape and the road gradient. As a result, it is possible to execute control such that the input shaft rotation number becomes equal to the final target input shaft rotation number based on the road information. Accordingly, for example, it is possible to reliably respond to differences in the expectation of the driver with respect to the vehicle acceleration change magnitude, depending on how gentle/sharp the corner is or the upward or downward gradient of the road. In addition, it is possible to slowly execute control of the shift ratio even when, for example, executing control of the shift ratio when running around the corner. Accordingly, it is possible to prevent the driver, or any other occupant, of the vehicle which is in the midst of turning, from feeling any sense of discomfort.
Also, according to the first aspect of the invention, the vehicle state information is information which includes at least one of the accelerator opening degree and the vehicle speed. As a result, it is possible to execute control such that the input shaft rotation number becomes equal to the predetermined target input shaft rotation number based on the road information. Accordingly, it is possible to reliably respond to differences in the expectation of the driver with respect to the vehicle acceleration change magnitude, depending on, for example, the accelerator opening degree or the magnitude of the vehicle speed.
Also, according to the first aspect of the invention, the road information control detection device detects the execution of control by the road information shift control device. Moreover, the continuous control detection device detects that shifting needs to be executed while control by the road information shift control device is continued, based on the detection result of the road information control detection device. As a result, it is possible to detect the need to continue control by the road information shift control device, by the actual execution of control by the road information shift control device.
Also, according to the first aspect of the invention, the downshift control detection device detects execution of the downshift control by the road information shift control device. Moreover, the continuous control detection device detects the need to decelerate while continuing downshift control by the road information shift control device, based on the detection result of the downshift control detection device. In addition, the shifting speed setting device sets the shifting speed, when control by the road information shift control device starts, to the predetermined shifting speed such that shifting is executed rapidly, and sets the shifting speed, when it is necessary to decelerate during control by the road information shift control device, such that the shifting speed is lower than the predetermined shifting speed, based on the detection result of the continuous control detection device. As a result, it is possible to rapidly decelerate when it is necessary to decelerate during control by the road information shift control device. Accordingly, it is possible to apply engine brake in accordance with the expectation of the driver.
Also, according to the first aspect of the invention, the shifting speed setting device sets the shifting speed on the occasion of executing upshift control, when the downshift control by the road information shift control device is completed and the corner is passed, such that the shifting speed is lower than the normal shifting speed. As a result, when returning from downshift control by the road information shift control device, the upshift is executed in a slow manner, and it is possible to satisfy the acceleration requirements expected by the driver. Accordingly, it is possible to prevent the driver or the occupant from feeling any sense of discomfort.
Also, according to the first aspect of the invention, the shift control device calculates the predetermined target input shaft rotation number when the operation indicating the intention of the driver to decelerate is detected. As a result, it is possible to start control by the shift control device based on the deceleration intention of the driver. Accordingly, it is possible to generate vehicle acceleration change in accordance with the expectation of the driver, and thus the driver is prevented from feeling a sense of discomfort.
Also, according to the first aspect of the invention, the ON and the OFF state of the accelerator pedal is detected and the control by the shift control device starts when the OFF state is detected. As a result, it is possible to reliably detect the deceleration of the driver, and thus the control by the shift control device can be started based on the deceleration intention of the driver.
Also, according to the first aspect of the invention, the opening degree of the throttle valve is detected and the control by the shift control device starts when the predetermined opening degree of the throttle valve is detected. As a result, it is possible to reliably detect the deceleration of the driver, and thus the control by the shift control device can be started based on the deceleration intention of the driver.
Also, according to the first aspect of the invention, the shift control device calculates the target input shaft rotation number which is intermittently calculated at the start of calculation based on the road information, after switching from the predetermined target input shaft rotation number calculated based on vehicle state information to the predetermined target input shaft rotation number calculated based on the road information. Alternatively, the shift control device calculates the target input shaft rotation number which is intermittently calculated during the continuation of the control based on the road information, within a predetermined time once the input shaft rotation number has reached substantially the predetermined target input shaft rotation number. Furthermore, the shifting speed setting device may set the shifting speed to the predetermined shifting speed before the input shaft rotation number reaches substantially the target input shaft rotation for when the control based on the road information is started. In addition, when it is necessary to execute control such that the input shaft rotation number becomes equal to the target input shaft rotation number during the continuation of control using the road information, it is determined that shifting needs to be executed during execution of continuous control by the shift control device, and the shifting speed control device sets the shifting speed such that the shifting speed is lower than the predetermined shifting speed. As a result, it is possible to set a shifting speed based on the control state of the input shaft rotation number which is in accordance with the predetermined target input shaft rotation number calculated based on the vehicle state information or the road information. Accordingly, it is possible to reliably respond to differences in the expectation of the driver with respect to vehicle acceleration change magnitude, depending on the vehicle state information or the road information.
According to the second aspect of the invention, the shift control device calculates the predetermined target input shaft rotation number with respect to the first specified corner based on road information and vehicle state information, and controls the input shaft rotation number such that the input shaft rotation number becomes equal to the predetermined target input shaft rotation number, by executing shifting of the shift execution device. Moreover, the continuous control corner detection device detects the second specified corner requiring control by the shift control device to be continued during control by the shift control device with respect to the first specified corner. Furthermore, the shifting speed setting device sets the shifting speed, based on the detection result of the continuous control corner detection device, such that the shifting speed for the first specified corner requiring control by the shift control device is different from the shifting speed for the second specified corner requiring control by the shift control device to be continued. As a result, it is possible to set the shifting speed such that it is different depending on whether the corner a vehicle is running around is the first specified corner requiring control by the shift control device or the second specified corner requiring the control by the shift control device to be continued. Accordingly, it is possible to respond to differences in the expectation of the driver with respect to the vehicle acceleration change magnitude for each corner. Thus, the driver is prevented from feeling a sense of discomfort.
Also, according to the second aspect of the invention, the shifting speed setting device sets the shifting speed, based on the detection result of the continuous control corner detection device, to the predetermined shifting speed such that shifting is executed rapidly when the vehicle is running around the first specified corner requiring control by the shift control device, and sets the shifting speed such that the shifting speed is lower than the predetermined shifting speed when the vehicle is running around the second specified corner requiring control by the shift control device to be continued. As a result, when the corner the vehicle is running around is the first specified corner requiring control by the shift control device, it is possible to generate large vehicle acceleration change. Alternatively, when the corner is the second specified corner requiring control by the shift control device to be continued, it is possible to generate a small vehicle acceleration change. Accordingly, it is possible to respond to differences in the expectation of the driver with respect to the vehicle acceleration change magnitude, depending on the corner which the vehicle is running around. As a result, it is possible to prevent the driver feeling a sense of discomfort.
According to the third aspect of the invention, the predetermined target input shaft rotation number is calculated based on the road information and the vehicle information, the input shaft rotation number is controlled such that the input shaft rotation number becomes equal to the predetermined target input shaft rotation number by execution of shifting of the automatic transmission, the shifting speed is set to the predetermined shifting speed such that shifting is executed rapidly when the control of the input shaft rotation number begins, and, the shifting speed is set such that the shifting speed is lower than the predetermined shifting speed when shifting needs to be executed during the control of the input shaft rotation number. As a result, the control by the shift control device can respond to differences in the expectation of the driver with respect to vehicle acceleration change magnitude, depending on whether the control by the shift control device is starting or in-progress. As a result, it is possible to provide a vehicle control method which prevents the driver or an occupant from feeling a sense of discomfort.
According to the fourth aspect of the invention, the vehicle control program causes the vehicle control computer to function as the shift control device which calculates the predetermined target input shaft rotation number based on the road information and the vehicle state information, and controls the input shaft rotation number such that the input shaft rotation number becomes equal to the predetermined target input shaft rotation number, by executing control of the automatic transmission. Furthermore, the vehicle control computer is also caused to function as the shifting speed setting device which sets the shifting speed to the predetermined shifting speed such that shifting is executed rapidly when control by the shift control device starts, and sets the shifting speed such that the shifting speed is lower than the predetermined shifting speed when shifting needs to be executed during the control by the shift control device. As a result, the control by the shift control device can respond to differences in the expectation of the driver with respect to vehicle acceleration change magnitude, depending on whether the control by the shift control device is starting or in-progress. As a result, it is possible to provide a vehicle control program which prevents the driver feeling a sense of discomfort.
For the purposes of this disclosure, device and means may be considered synonyms. Both relate to a computer and its programs and encompass any necessary memory. The device may be implemented solely by circuitry, e.g. hardware, or a combination of hardware and software. Further, in some cases, as defined in the specification, the device/means may include other elements.